/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.dubbo.rpc.protocol.tri.rest.mapping.meta;

import org.apache.dubbo.common.utils.ClassUtils;

import java.util.Set;
import java.util.stream.Collectors;

import com.google.protobuf.Descriptors.Descriptor;
import com.google.protobuf.Descriptors.FieldDescriptor;
import com.google.protobuf.Message;

final class ProtoBean {

    public static final boolean HAS_PB = ClassUtils.hasProtobuf();

    public static Set<String> getFields(Class<?> clazz) {
        if (HAS_PB && Message.class.isAssignableFrom(clazz)) {
            try {
                Descriptor descriptor =
                        (Descriptor) clazz.getMethod("getDescriptor").invoke(null);
                return descriptor.getFields().stream()
                        .map(FieldDescriptor::getName)
                        .collect(Collectors.toSet());
            } catch (Exception ignored) {
            }
        }
        return null;
    }
}
